The background of the invention will be set forth in two parts.
1. Field of the Invention
The present invention pertains generally to the field of locking devices and more particularly to a new and useful kingpin lock for semi-trailer type travel trailers.
2. Description of the Prior Art
U.S. Pat. Nos. 2,656,706 and 3,982,413 were discovered on a prior art search and constitute the only prior art presently known to applicant.
U.S. Pat. No. 2,656,706 discloses a split-collar lock for a fifth wheel kingpin, the kingpin having an annular groove, the collar including two substantially semi-annular hinged sections, the sections being the same thickness as the annular groove and the inner diameter being substantially equal to the diameter of the annular groove whereby the sections close around the kingpin within the annular groove. One of the sections has a slot in which a latch is pivotally secured. The opposing section has a similar slot, the latch engaging a catch portion bridging the last-named slot when the sections are in locking position. The latch has a notch adapted to engage the catch portion to securely link the two sections in locking position. A key-operated bolt is adapted to engage the latch to secure the latch in locking position with the catch.
U.S. Pat. No. 3,982,413 discloses a lock collar comprising a pair of generally semi-circular similar locking segments each having a pair of mating, overlaping end portions of reduced thickness. The mating portions of one end of the locking segments are connected together by a pivot pin. The mating portion of the other end of the segments are provided with lock-receiving passages through which a lock element passes. The passage of one segment has a latch-receiving keyway and the lock element includes a spring latch element permitting the same to be snapped into locking position within the keyway when the segments are in closed position.
While generally satisfactory, lock collars of the types disclosed in these two patents, have the disadvantages that they are difficult to install on a kingpin covered with grease and dirt and the key-operated locking elements may become fouled by this grease and dirt.